An underwater data center powered by tidal energy has been proposed off the coast of Maine.

DeepGreen Western Passage SPV LLC wants to build the 51MW power project in the Western Passage, a stretch of water near the town of Eastport that links into the Atlantic Ocean.

The company has submitted an application to the Federal Energy Regulatory Commission (FERC), requesting a 48-month permit to conduct environmental studies and engineering work in the Western Passage.

Details of the project were first reported by local news outlet The Quoddy Tides.

According to the application, DeepGreen Western Passage intends to build “universal docking cradles” on the ocean floor, into which it will be able to plug energy-generating turbines, as well as pods containing AI compute infrastructure.

The initial deployment would contain 170 turbines and 34 data center pods, the application said. Turbines will provide power for the servers, and send energy to residents and businesses in Eastport, as well as the Passamaquoddy Tribe, an American First Nation based in Maine and over the border in New Brunswick, Canada.

It is anticipated that the project will cost $415 million, funded from DeepGreen’s own resources and other backers.

In comments to the Quoddy Times, DeepGreen’s Louis Wolfson said the company is also exploring a similar project at Cook Inlet, Alaska. Wolfson said the company intends to use “proven technologies,” and that it is exploring various funding options.

The project is seemingly unrelated to UK startup Deep Green, which is developing its own terrestrial facilities in the UK and US.

Underwater data centers have yet to make a big splash, but several projects have explored the potential of submerging servers to take advantage of the natural cooling properties of the ocean.

Chinese company HiCloud says it has underwater data center modules operating commercially, having installed its servers 35m deep on the seabed off the coast of Lingshui Li County, Hainan Province, in 2023.

More recently, it launched a project connecting these data centers directly to offshore wind farms, and said it was targeting 500MW ocean deployments.

Data center startup Subsea Cloud already claims to operate 13,500 servers in underwater locations in Asia, which will be rented to AI companies and those in the gaming industry. With permits secured, it hopes to be up and running next year, and says its servers do not impact the ocean’s temperature.

Another company, NetworkOcean, wants to test underwater data centers in San Francisco Bay, but has reportedly run into permitting issues, and now appears to be experimenting with floating servers.

These companies may want to heed the fate of Microsoft’s Project Natick, which saw a subsea data center deployed off the coast of Scotland in 2018. The test system contained 855 servers, which were left unattended for 25 months and eight days. The company left 135 servers in a normal data center, alongside hardware running Microsoft’s Azure cloud, to compare and contrast.

Speaking to DCD in 2024, Noelle Walsh, the head of the company’s Cloud Operations + Innovation (CO+I) division, said the project was over. “I’m not building subsea data centers anywhere in the world,” Walsh said.